Wikipedia
Macpup
Macpup is an operating system based on Puppy Linux, which has Puppy's normal JWM window manager available, but also includes the Enlightenment WM; users can quickly switch window managers without rebooting. The Macpup Enlightenment interface as installed features a Mac OS X-like dockbar, but many Enlightenment themes are available. Macpup comes with the Firefox web browser, and like its parent, Macpup can be run from RAM. The live .iso only uses 184MB of RAM.